Surface modified porous polytetrafluoroethylene (PTFE) membranes are being considered for filtering a variety of fluids, for example, for removing trace metal impurities from microelectronics fluids. Some of these membranes are characterized by low surface energy values or critical wetting surface tension (CWST) values and/or high resistance to organic solvents and aggressive chemicals. Despite the one or more of the advantages of these membranes, there exists a need for PTFE based membranes with improved properties such as low CWST values and/or increased resistance to organic solvents and/or aggressive chemicals.